const NEW_PRO:&str = "123456";

fn main() {
    let spaces = "   ";

    println!("spaces is {}",spaces);

    // shadowing one
    let spaces = 123456;
    
    println!("Hello, world! {}",NEW_PRO);

    println!("Hello, world! {}",spaces);

    let guess:u32 = "42".parse().expect("Not a number!");

    // 整数类型 整数字面值
    
    let sum  = 5; 
    
    // 复合类型
    let tup = (50, 6.4, 1);

    println!("{},{},{}",tup.0,tup.1, tup.2)
    
    // 数组
    let b = ["Jan","Feb"];
    
    // [类型;长度]
    let c:[i32;5] = [1,2,1,1,1];
}